Recent content by robotype

I'm helping a friend remotely so I haven't inspected the monitor personally yet, I just told him try to tweak the pots to see if anything changes but that won't help, maybe bad pot/solder? or what else could have gone bad? stuck transistor for the green? looks like blue and red are present.

also replaced ZD431 which solved a similar issue for someone else but didn't help in my case.

HA11423 replaced but I still have a line accross the screen.

One day I turned it on and I got an horizontal line in the middle of the screen. Currently I've replaced capacitors (C431, C432, C433), resistors (R433, R436) and two D1138 transistors...and all was ineffective. Where would I be looking next?

success! today I swapped the two dacs and I confirmed U20 is bad. Thanks jacklick for the precious help. After many years both my Q*Berts are finally working. I also recapped the g07 and replaced a resistor R908 that prevented it to turn on (B+ was over 150vdc and impossible to adjust). The...

Fixed voice pitch by turning R6. Then scoped all DAC1408 outputs and U20 signal looks just a bit "dirty" compared to the other ones...I could try replace that but I don't have a spare right now. (I also attached an external amp directly to the outputs for the dacs and the opamps and I hear the...

lol no I haven't been working for ten years on this...the game went forgotten behind other cabinets for many years and reappeared recently :) #1 so yes! yesterday I replaced the bad LM379S and that was the obvious cause for the silence on the first pcb, so now I have one working sound board and...

replaced 74LS04@U16 on the sound board but didn't help.

thanks for the link! I get all the sound, nothing is missing but the interlude jingles play garbled... I will try replace that 74LS04 as suggested (already replaced A10).

replaced a 470μ and 5 x 47μ caps but it didn't cure it I want to try replace the sound rom

sorry to bump but did you fix this? Me too I have the high-pitched noise on two boards. moved romset on a known working pcb and same problem! also, my duck hunt pcb won’t work with one RP2A cpu, needs the one on the other side as well...

saw another repair log, probably the soldered Z80A on the top is bad

just got one missing sprites and the bottom pcb is 100% ok! so fault must be on top pcb. any clue?

I have a metamorphic force I need to find it and test it, eventually interested in sengeki / punisher

anode cap was coming off, that's what caused the image size flickering! so now I know what happens when you remove an anode cap from a crt while it's switched on :)